The present invention relates to medical devices for securing tendons and ligaments to bones in order to stabilize a joint. More specifically, the present invention is focused on an entirely arthroscopic approach and the benefits that provides (reduced procedure time, recovery time, invasiveness and morbidity), without sacrificing fixation strength. Moreover, the present invention provides additional benefits including reduced destabilization and rotation of implants during deployment, mating, and final positioning.
Many of the contemporary medical devices for anchoring tendons and ligaments to bone provide some benefits only at a cost. The current gold standard for achieving superior fixation strength is to use interference screws but these require an open (non-arthroscopic) approach. For example, Arthrex' Bio-Tenodesis, and Tenodesis Screw systems can be difficult to use in an arthroscopic approach. Open approaches involve greater invasiveness, morbidity, and healing time as compared to endoscopic and arthroscopic techniques. The fixation strength of tenodesis interference screws averages about 234N for ultimate pullout resistance. (See David P. Richards, M.D., F.R.C.S.C., and Stephen S. Burkhart, M.D., A Biomechanical Analysis of Two Biceps Tenodesis Fixation Techniques, Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 21, No 7 (July), 2005: pp 861-866.)
Even excluding the drawback of an open approach typically required for using interference screws, they are not a perfect solution to the tenodesis repair problem. Using a tenodesis interference screw also requires an additional procedural step of whipstitching the tendon graft prior to using the fixation device. This step requires externalization of the tendon from the articular working space, a task disliked by many surgeons because it requires additional procedure time and can be difficult to perform. Additionally, most surgeons will find it necessary to remove surrounding cortical bone in order to fit both the device and the tendon into a tunnel or bore drilled into bone. This is an additional step that would preferably be omitted from the tenodesis procedure. If each procedure takes less time and difficulty, surgeons can perform more procedures per day and improve accuracy and efficiency.
Another disadvantage of relying on interference screws for tenodesis repair is that it can be difficult to recreate an anatomical fixation when using them. As the screw is rotated to seat it into the tunnel, the tendon often rotates along with the screw. The tendon can in that manner become wrapped around the screw and moved from its original placement. This undesirable process simultaneously alters the tension originally set by the surgeon in the muscle-tendon-bone complex and changes the intended mechanics of the fixation. A related difficulty of utilizing these devices lies in setting the initial graft tension. For example, in proximal biceps tenodesis, many surgeons report that it is difficult to set the proper tension to the biceps muscle if using a tenodesis interference screw for tendon fixation.
Current arthroscopic approaches generally provide significantly weaker fixation strengths, for example, ultimate pullout forces in the mid to low 100N range. One of the simpler options currently available to perform an arthroscopic tenodesis repair is to use a suture anchor, such as the Depuy-Mitek G2 system. These devices require suturing the end of the tendon, placing an anchor into a decorticated bleeding bed at the desired fixation site, and then approximating the tendon to the attachment point by tensioning the sutures through the anchor and knotting them in place. Although this is a relatively easy procedure to complete arthroscopically, the fixation strength is limited by the holding force of the suture in the soft tissue of the tendon.
Accordingly, there is a need for a streamlined arthroscopic tenodesis repair procedure along with an integrated device for performing such procedure that avoids time-consuming preparations (whipstitching, externalization of the tendon) and provides greater fixation strengths comparable to those obtained through open techniques using interference screws. Additionally, there is a need to avoid the drawbacks of interference screws including especially, rotation of the tendon around the screw and deviation of the original tensions set by the surgeon caused by displacement of the muscle-tendon-bone complex and tendon graft.